The predominant protein in human seminal coagulate

Abstract

Lilja H, Laurell C-B. The predominant protein in human seminal coagulate. Scand J Clin Lab Invest 1985; 45: 635–641. The predominant protein in human seminal vesicle secretion constitutes the structural protein of coagulated semen. This high molecular weight protein (HMW-SV-protein) is stable in seminal vesicle secretion during in vitro storage at 37 d`C for at least 20 h, but is rapidly cleaved on mixing with prostatic proteases. Seminal coagulate, washed free of souble components, is dissoluble by 2 to 3 mol/1 of guanidine-HCl. Although dithiothreitol added to seminal coagulate does not liquify the clot, complexes between HMW-SV-proteins are broken up by reduction under denaturing conditions, which suggests that the non-covalent linkages of HMW-SV-proteins are essential in the clot. Prostatic proteases cleave the HMW-SV-protein during liquefaction of ejaculated semen to a series of labile proteins. These proteins are further cleaved to peptides of successively decreasing size after completed liquefaction. The cleavage of the HMW-SV-protein is the major cause of the fast shift of the electrophoretic pattern of seminal proteins if semen is stored without protease inhibitors.